Introduction

The present invention refers to a method for purifying zootechnical and industrial wastewater rich in nitrogen and phosphorous through the use of natural zeolites. The method enables an optimal reduction of the ammoniacal nitrogen to allow the precipitation of struvite reducing the amount of reagents that would be required if the struvite would be crystallized straight at the beginning. In this way the costs are reduces, and no excessive chemical species are introduced into the treated wastewater.

Technical features

The present invention relates to a method for the removal of nitrogen (N) and phosphorus (P) from industrial digestates and livestock manure or all substances in a liquid state that contain these two elements. These elements are not lost but are transferred and stored in solid phases, recoverable and usable again. The materials obtained at the end of the process can be used as fertilisers (zeolitite, struvite and (N) and (P) depleted wastewater). The materials obtained at the end of the process can be used as fertilisers (zeolitite, struvite and N- and P-depleted wastewater).

Possible Applications

• Biogas production;
• Liquid digestates;
• Agricultural fertilisers and soil improvers market;
• Zootechnical waste treatment to reduce the nutrients load.

Advantages

• Reduction of P and Mg reagents to the effluent
• Zeolitite raises wastewater pH
• The possibility of obtaining Nitrogen-rich natural zeolites combined with struvite from a single system